EXPERIMENTAL STUDY ON FLOOR IMPACT SOUND AND HARDNESS DURING FALLING COLLISION AND WALKING FOR TATAMI

Abstract

　The "floor" that is in constant contact with people is important for users to spend comfortably and safely in the architectural space. Improving floor performance (safety and comfort) is considered to be an important issue for all generations, including children, adults and the elderly.

　The purpose of this study is to be safe and comfortable for children and the elderly, and to solve the problem of floor impact sound. It is "Development of tatami with consideration for sound insulation performance and safety and formulation of design guidelines".

　In this paper, we first focused on tatami as a basic study. We examined heavy-weight floor impact sound, the hardness at the time of a fall collision, and the hardness at the time of walking. In addition to commercially available straw tatami and building material tatami, five types of tatami mats focusing on vibration isolation were prototyped and experimentally examined. For reference, we also examined light-weight floor impact sound.

　As a result of this paper, the following findings were obtained.

　1) Straw tatami and building material tatami had no effect on the heavy-weight floor impact sound level reduction in the 63 Hz band, and were about 0 to -1 dB. In tatami mats that was prototyped in this paper, considering the vibration isolation, we were able to achieve a performance improvement of 3 dB by reducing the heavy-weight floor impact sound level in the 63 Hz band.

　2) Regarding the hardness at the time of a fall collision, straw tatami and building material tatami were 50 to 53 G. The prototype tatami mats had a large impact mitigation effect of 20 to 31 G.

　3) Of the prototype tatami mats that were able to realize (1) and (2), T4 and T5 were also good for walking.

　4) Regarding the four types of performance related to floor hardness, the relationship of quantitative evaluation of each performance was clarified. It turns out that none of the performances correspond linearly. It was suggested that it is necessary to examine each layer in the floor cross section and the combination of each layer for each performance.

　As described above, in this paper, it was found that the prototype tatami mat does not impair the walking feeling, and the effect can be obtained by the amount of reduction in heavy-weight floor impact sound level and the hardness at the time of a fall collision. In addition, the effectiveness of introducing such a vibration-proof structure into tatami mats was suggested.